Remove all MusicBrainzCheckDate objects, clean up MusicBrainz scan
Move InsertFolder database interaction to repository
Move media item inserts into repositories
Add logging and non logged functions to IDatabaseExtensions
Move update session to repository
Make all timestamps UTC everywhere, remove local timestamp since we didn't use it
Merge pull request #204 from mdlayher/master

Remove all MusicBrainzCheckDate objects, clean up MusicBrainz scan